I didn't see anyone in the comments mention Lazarus yet, so i thought that i'd go ahead and do that: https://www.lazarus-ide.org/
It's a free IDE for FreePascal and a set of useful packages that work out of the box and give you a "batteries included" development experience, for CLI apps, desktop software and even some simple web development (though admittedly most other languages do web development better). Here's more information about the component libraries: https://en.wikipedia.org/wiki/Free_Component_Library and https://en.wikipedia.org/wiki/Lazarus_Component_Library
Where it shines in my experience is creating GUIs: making a framework that works atop of the system native functionality and abstracts it away was a really good idea - you get a consistent development experience across the platforms (as long as you don't try doing anything too sophisticated) without having to use a common runtime, like Electron makes you. This results in native looking, snappy and not too resource intensive programs. There's even a gallery of what others have made with it here: https://wiki.freepascal.org/Projects_using_Free_Pascal
There are few other platforms that i'd reach for if i'd want reasonably performant desktop software development in a small runtime and with an easy development experience: maybe the old Java Swing or OpenJFX since those are cross platform. Avalonia for .NET doesn't seem quite as stable yet and using Qt Designer would be a tad complex since i'm not intimately familiar with C++ and enjoy languages with simple memory management.
It's a free IDE for FreePascal and a set of useful packages that work out of the box and give you a "batteries included" development experience, for CLI apps, desktop software and even some simple web development (though admittedly most other languages do web development better). Here's more information about the component libraries: https://en.wikipedia.org/wiki/Free_Component_Library and https://en.wikipedia.org/wiki/Lazarus_Component_Library
Where it shines in my experience is creating GUIs: making a framework that works atop of the system native functionality and abstracts it away was a really good idea - you get a consistent development experience across the platforms (as long as you don't try doing anything too sophisticated) without having to use a common runtime, like Electron makes you. This results in native looking, snappy and not too resource intensive programs. There's even a gallery of what others have made with it here: https://wiki.freepascal.org/Projects_using_Free_Pascal
There are few other platforms that i'd reach for if i'd want reasonably performant desktop software development in a small runtime and with an easy development experience: maybe the old Java Swing or OpenJFX since those are cross platform. Avalonia for .NET doesn't seem quite as stable yet and using Qt Designer would be a tad complex since i'm not intimately familiar with C++ and enjoy languages with simple memory management.